Distributed control network for irrigation management

ABSTRACT

A system and method for operating a distributed control network for irrigation management. The system incorporates several irrigation controllers wherein each of the controllers can transmit, receive and respond to commands initiated by any device or satellite controller on the network, a communication bus that is connected to the controllers, a central computer that is connected to the bus, several sensing devices that are connected to each controller, and several sprinkler valves that are connected to each controller. The controllers can be operated in local mode via a user interface and in a remote mode via a wireless connection. The controllers are capable of monitoring and acknowledging the commands that are transmitted on the bus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an irrigation control system. Moreparticularly, the invention relates to a peer-to-peer irrigationsprinkler control system with the ability to monitor and control theentire system from any satellite controller.

2. Description of the Related Art

In the area of irrigation management and control, there are twosignificant types of control systems that are used: the stand-alonecontroller and the central-satellite system. FIG. 1 shows a traditionalstand-alone controller 1, which is typically used for smaller irrigationsites, with outputs varying from four (4) to approximately forty eight(48) outputs. The stand-alone controller 1 is a device that is usuallywall mounted, and offers a user interface such as a keypad and a liquidcrystal display. With the user interface, a user can set up automaticwatering programs, perform manual watering, as well as perform someadditional functions for irrigation control.

Connected to the stand-alone controllers 1 are sensors 3 and irrigationsolenoid valves 5. The sensors 3 monitor multiple variables thattypically include the amount of rainfall, water flow and powerconsumption. Then, the sensors 3 provide this data to the stand-alonecontroller 1. Also connected to the stand-alone controller 1 are aplurality of valves 5. The valves 5 are typically 24 VAC solenoidoperated valves. The valves 5 are connected to the stand-alonecontroller 1 with field wiring 7 that delivers the 24 VAC to the valvesolenoid.

The stand-alone controller 1 provides valve control and records sensordata as input to various programmable features. The controllers 1 areset-up and programmed via a graphical user interface on the controller.It is known in the art that typical irrigation controllers containmicroprocessors as disclosed in U.S. Pat. No. 5,956,248, by Williams etal.

In larger installations, multiple stand-alone controllers must be usedbecause the distance between the controller and valve stations islimited by a maximum amount of tolerable wiring impedance. However,sites that utilize multiple stand-alone controllers are difficult tomaintain because they must be managed independently at the location ofthe installation.

An alternative to the multiple stand-alone controllers solution forlarge installations is a conventional central-satellite control systemshown for example in FIG. 2. U.S. Pat. No. 4,244,022 entitled“Irrigation Control System ” by Kendall, discloses a master-slave typecontrol system for large-scale irrigation that incorporates a centralcomputer 9 connected to a plurality of satellite controllers 11 whichare in turn connected to control irrigation solenoid valves.Central-satellite control systems generally consist of various senseand/or control devices linked together via a communication bus 13. Thisdistributed control methodology allows the management of large sitesfrom a single location. A typical installation will contain multiplefield controllers, or satellites 11, and a single central control center9. The central control center is managed by a personal computer 9.

The satellite controller 11 is a field device, similar to a stand-alonecontroller, that offers both valve solenoid control and various sensorinterfaces. More sophisticated satellites also have a user interface forlocal programming.

A major difference between the satellite controller 11 and thestand-alone controller 1 is the communication bus 13 interface. Thecommunication bus 13 interface allows the satellites 11 to communicatewith the remote central computer 9. The type of communication bus 13varies depending on the requirements of each individual site. Typicalcentral-satellite systems use twisted pair wire, radio modems, analogtelephone modems, wireless communication (RF VHF, UHF, microwavefrequencies), fiber optics, power lines, telephone cables, cellulartelephones, infrared, wireless pager systems, or television cables forthe communication bus.

In managing large installations, the central-satellite system has someadvantages over using multiple stand-alone controllers. Thecentral-satellite system significantly reduces the manpower and level ofeffort required to maintain a large installation. For example, problemsat a satellite location can be instantly reported to the centralcomputer. Also, complex watering schedules can be realized, such asthose based on evapotranspiration, by utilizing the computer's graphicaluser interface and processor capabilities. U.S. Pat. No. 5,208,855 byMarian, discloses one such method and apparatus for irrigation controlusing evapotranspiration. U.S. Pat. No. 5,870,302 by Oliver discloses asystem and method for using evapotranspiration in controlling automatedand semi-automated irrigation systems.

Despite the advantages of the central-satellite system, problems stillexist with this system. The cost of a central-satellite system can bevery high. For example in a smaller site consisting of 5-10 satellitecontrollers, the costs associated with operating and maintaining acentral computer are not feasible, even though a networked solution ispreferred. Additionally, there is a large and difficult learning curvefor a system operator to fully understand and utilize the capabilitiesof the system. Moreover, the satellites are mostly simple receivers thatcan only communicate on the bus when specifically addressed by thecentral computer.

The Oliver patent discloses that satellite controllers may communicatewith other satellite controllers but only to pass data along from acommunications and electronic control device. The Oliver patent does notdisclose satellite controllers that are capable of monitoring andcontrolling the entire irrigation control system. Similarly, U.S. Pat.No. 5,740,031 by Gagnon, discloses irrigation controllers that cantransmit and receive communications with other irrigation controllersand computer interfaces but in the capacity of a repeater when thecentral computer can not communicate directly with a controller due tosignal attenuation and/or reflection. Again, Gangon does not disclose anirrigation controller capable of monitoring and controlling the entiresystem. If the central computer fails, then the entire system mustoperate as individual stand-alone controllers. The present inventionprovides a system, method and apparatus to meet these needs and addressthese deficiencies.

BRIEF SUMMARY OF THE INVENTION

The present invention is a system, method and apparatus for managing andcontrolling irrigation by forming an irrigation control system. Theirrigation control system forms a peer-to-peer network of satelliteirrigation controllers, as opposed to known master-slave orclient-server type systems. The present invention may be monitored andoperated from a central computer or at any one of the satellitecontrollers. The use of peer-to-peer architecture allows any satellitecontroller to address any other satellite controller. Thus, the user canmonitor and control the entire system from any satellite controller, ornode in the network. The invention provides peer-to-peer control of theentire system at each satellite controller through the use of a highspeed micro-controller.

The present invention can be used to meet any type of irrigation needs.For example, the irrigation control system can be used to irrigate bothlarge and small areas. When the system is used to irrigate large areas,a central computer is connected to the communication bus and becomespart of the peer-to-peer network. The central computer provides theadditional computing power needed to manage large irrigation sites. Thecentral computer provides a convenient centralized site, for example,for collecting, downloading and programming information. After two orthree controllers, the central computer is a desirable feature. Forother smaller irrigation sites, the central computer is not needed. Thecentral computer could be any computer, such as a personal computer.

As mentioned above, each satellite controller utilizes a high-speedmicro-controller to accomplish its functions. A flash memorymicro-controller is acceptable. A primary responsibility of themicro-controller is to monitor and control the communication bus. Thebus is a half-duplex communication bus that allows only one device totransmit at any one time. In order for the peer-to-peer architecture tofunction, proper bus management is imperative to ensure reliablecommunication between the devices.

The present invention includes a software algorithm used by themicro-controller to monitor and control the communication bus. Thesoftware algorithm minimizes bus collisions and provides a messageacknowledgement scheme to the transmitting device providing feedback ofa successful transmission. If acknowledgements are not received within aprescribed amount of time, a number of transmit retries can be useduntil the acknowledgement is detected or the operation is aborted. Ifthe operation is aborted, then an alarm condition is recorded.Furthermore, the messages are packaged into small packets of data,allowing all devices an opportunity to take control of the bus.

In the present invention, the communication bus can take a variety ofconventional forms.

One example of flexibility of the peer-to-peer architecture is realizedby using a DTMF radio receiver, which receives and decodes tones fromhandheld radios for remote system control. The DTMF radio receiver isoptimally placed at any node in the network. A DTMF message is sent tothe receiver and the message is prefaced with a specific satellitecontroller address. The receiver then forwards the message onto thecommunication bus and the message is received at the specified satellitecontroller. (Other conventional systems require a central computer forsatellite to satellite communications.)

According to the invention, there is provided a system for operating adistributed control network for irrigation management. There areirrigation controllers, each of the controllers being responsive to acommand from an other controller, wherein the controllers are capable oftransmitting, receiving and responding to a command, and wherein thecontrollers can be operated in a local mode via a graphical userinterface and in a remote mode via a wireless connection. There is acommunication bus, connected to the controllers, wherein the controllersare capable of monitoring commands and the controllers are capable ofacknowledging the commands. Also provided is a central computer,connected to the bus, communicating with the controllers via the bus.There are sensing devices connected to each of the controllers.Sprinkler valves are connected to the controllers.

Further in accordance with the invention, there is provided a method foroperating a distributed control network for irrigation management. Thereis a step if initiating a command at one of several irrigationcontrollers, wherein said controllers are connected to sensing devicesand sprinkler valves. There is a step of transmitting the command fromthe controller to an other controller via a communication bus. There isalso a step of monitoring the command on the communication bus by thecontroller. There is a step of receiving the command at the othercontroller, acknowledging said command by the other controller, actingon said command by the other controller; and providing a connection froma central computer to the controllers on the communication bus.

These and other objects, features and advantages of the presentinvention are readily apparent from the following drawings and detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a prior art stand alone controller.

FIG. 2 is a block diagram of a prior art Central-Satellite (master-slaveor client-server) irrigation control system.

FIG. 3 is a block diagram of a peer-to-peer irrigation control system.

FIG. 4 is a flowchart of a software algorithm used by a micro-controllerin satellite controllers to provide a message acknowledgment scheme andto give the transmitter feedback for a successful message transmission.

FIG. 5 is a flowchart of the software algorithm used by themicro-controller to monitor a communication bus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is made to FIG. 3, which depicts the block diagram of thedistributed control network for irrigation management. The controlnetwork is a peer-to-peer network wherein the entire system, or anyportion thereof, can be monitored and operated from any node in thenetwork. Several satellite controllers 15 are connected to one another,and further connected to a central computer 25, all via a communicationbus 23. FIG. 3 is not meant to limit the number of satellite controllers15 that can be connected to the communication bus 23. The satellitecontrollers 15 operate as nodes in the peer-to-peer network wherein theentire control system can be monitored and operated.

In the system depicted in FIG. 3, the satellite controllers 15 perform avariety of functions. The satellite controllers 15 control the solenoidoperated valves 17 and interface with various sensors 21. Any standardsolenoid is acceptable. Preferably, the satellite controller can operateup to 96 valves.

The satellite controllers 15 can be operated both locally at thesatellite controller and remotely from other devices on the bus 23. Whenthe satellite controller is in local mode, the satellite controller 15can operate the valves that feed directly off of that controller. Forexample, one might operate the satellite controller 15 in local mode,for example, to do maintenance. One might operate the controller inlocal mode, for example, to do maintenance. Preferably, operating inlocal mode has no effect on programmed watering schedules. The satellitecontrollers 15 are operated in local mode advantageously via a graphicaluser interface attached to the satellite controller 15. The satellitecontroller preferably includes an LCD user interface.

In addition to operating in local mode, the satellite controller 15 canbe operated in remote mode. When operated remotely, the satellitecontroller 15 can be monitored and controlled from any node in thenetwork, such as the central computer 25 or any other satellitecontroller 15. The satellite controller 15 is typically operatedremotely to recognize complex watering schedules such asevapotranspiration. The user can remotely control a satellite controller15 which in turn can control some or all of the other satellitecontrollers 15. Thus, a significant advantage, the ability to sharesystem resources, is realized by utilizing the peer-to-peerarchitecture. All controllers 15 can be repeaters, and can maintainlinks to all other controllers. All controllers 15 can read or sensedata on any other controller on the bus.

In one variation of the invention, a DTMF radio receiver, which receivesand decodes tones from handheld radios for remote systems, can beoptimally placed at one of the satellite controllers 15. The user cansend a DTMF message to the receiver that can be addressed to anysatellite controller 15. The DTMF message is prefaced with a satelliteaddress and is forwarded on the bus from the satellite controller 15with the receiver to the controller that was addressed in the message.Thus, the message is received and forwarded on the bus to the specifiedsatellite controller 15.

The satellite controllers 15 can perform a variety of functions, whetherin local or remote mode. From the controller 15, the user can manuallyinitiate watering of an irrigation site which overrides any automaticwatering schedule. At front controller 15 or another controller on thenetwork, the user can also adjust/review manual operation, sensorreview, and watering schedules, at any other controller on the network.Additionally, the satellite controllers 15 can be programmed to realizecomplex watering schedules based on the input received from its sensors21 such as evapotranspiration. Additional functions performed by thesatellite controllers 15 include, for example, that sensors, programs,control functions can be transmitted onto the network for review, actionfrom, and by any other satellite, central computer, or remote handhelddevices.

An appropriate satellite controller is commercially available under thetrademark Tora LTD Plus™ or Rainbird Par™, for example. However, othercontrollers are also adequate and available.

Connected to each satellite controller 15 is a plurality of sprinklervalves 17. The sprinkler valves 17 are solenoid operated and areconnected to the satellite controller 15 via field wiring 19. The fieldwiring 19 delivers 24 VAC to the valve solenoids.

Also connected to each satellite controller 15 are various sensors 21that provide input to the controller 15. The sensors 21 typicallymeasure rainfall, water flow, water pressure, temperature, wind speed,wind direction, relative humidity, solar radiation, and powerconsumption.

As shown in FIG. 3, the satellite controllers 15 are connectedindirectly to one another via a communication bus 23. The type ofcommunication bus 23 can vary depending on the requirements of eachindividual site. Typical systems will be implemented with twisted pairwire, radio modems, analog telephone modems and so forth. Thecommunication bus 23 is preferably a half-duplex communication bus thatallows only one device to transmit at any one time, to avoid datacollisions on the bus. Full duplex is an option.

Also shown in FIG. 3 is the central computer 25 that is connected to thecommunication bus 23. The central computer 25 can be remotely locatedfrom the satellite controllers 15 and has the capability to monitor andoperate the entire system. The central computer 25 is typically used formanagement of large irrigation sites. One advantage of the presentinvention, is that the central computer 25 is not always necessary. Inprior art inventions, the central computer 9 was necessary in order tomonitor and control all of the satellite controllers 11 because thesatellite controllers 11 were not capable of monitoring and controllingthe entire system. However, in the present invention, the monitoring andcontrol functions can be performed at any satellite controller 15. Thus,the central computer 25 is not necessary for all applications.Typically, the central computer 25 will be present for large irrigationsite management and will not be present for smaller irrigation sitemanagement. Central computers may poll satellite controllers and thenreact by adjusting schedules, etc., and to download new schedules. Ageneral purpose computer, such as the IBM™ PC, is appropriate.

FIG. 3 also illustrates a remote device 25, here a hand held unit. Ifthe central computer 25 becomes disconnected from the bus 23, or ifcommunications are disrupted, communications can occur via bus 23 andthe remote device 25, via a remote connection 27.

Referenced in FIG. 4 is a flowchart of an appropriate software algorithmused by the micro-controller in a satellite controller 15 to provide amessage acknowledgment scheme and to give the transmitter feedback for asuccessful message transmission. The algorithm is designed to ensureproper bus management by the micro-controller. Other appropriatealgorithms will work, and, indeed, one of skill in the art willappreciate similar algorithms.

Reference is made to FIGS. 3 and 4. Step 401 is the transmit operation.At step 403, a message is queued in a free transmit buffer. Step 405queries whether the communication bus 23 is clear. If the bus 23 is notclear, then step 405 is repeated. If the bus 23 is clear, then themessage is transferred from the transmit buffer to a transmit port atstep 407. Next at step 409, a retry counter and a message timeoutcounter are set-up. After the counters have been set-up, then step 411transmits the message from the transmit port to the specified data port.Step 413 queries whether a message acknowledge is has been received. Ifthe message has been acknowledged, then the message queue is cleared atstep 415 and the transmit operation ends at step 427. The bus 23 is thenavailable for other transmissions.

However, if the message has not been acknowledged at step 413, then itproceeds to step 417 where the message timeout counter is decremented.Step 419 queries whether the timeout counter has expired. If the counterhas not expired, then the process goes back to step 411. If the timeoutcounter has expired, then step 421 resets the message timeout counterand decrements the message retry counter. Step 423 queries whether themessage retry counter has expired. If the retry counter has not expiredat step 423, the process returns to step 411. If the message retrycounter has expired, then step 425 clears the transmit queue and theevent is logged as a transmit error alarm. The end transmit operationthen occurs at step 427.

Referenced in FIG. 5 is a flowchart of the software algorithm used bythe micro-controller in each satellite controller 15 to monitor thecommunication bus 23. Step 501 signals the bus monitor operation. Atstep 503, a communication port is read. Step 505 queries whether theport is currently active. If the communication port is currently active,then step 507 generates a random number is loads the number into a delaycounter. Step 509 deasserts the bus clear flag. The bus monitor processis ended at step 517.

However, if the communication port is not active at step 505, then step511 decrements the delay counter. Then, step 513 queries whether thedelay counter has decremented to zero. If the delay counter is not atzero, then the process goes back to step 503 and repeats the process. Ifthe delay counter is at zero, then step 515 asserts the bus clear flag.Then, the bus monitor process is ended at step 517.

While the preferred mode and best mode for carrying out the inventionhave been described, those familiar with the art to which this inventionrelates will appreciate that various alternative designs and embodimentsfor practicing the invention are possible, and will fall within thescope of the following claims.

What is claimed is:
 1. A peer-to-peer distributed network system formanagement and/or control of irrigation, comprising: (A) a plurality ofirrigation controllers, each of said irrigation controllers transmittingat least one command to at least one other of said irrigationcontrollers, and each being responsive to at least one command receivedfrom said at least one other controller; (B) a communication busconnecting each of said irrigation controllers, wherein said at leastone command is transmitted from one of said irrigation controllers tosaid at least one other irrigation controller on said communication bus;and (C) wherein said at least one transmitted command includes at leastone command initiated at said irrigation controller and not repeatingsaid at least one received command.
 2. The system claimed in claim 1,wherein each of said irrigation controllers initiates and transmits aplurality of commands, including said at least one command, on saidcommunication bus.
 3. The system claimed in claim 1, wherein at leastone of said irrigation controllers is operated from a remote locationvia a wireless connection communicating therewith.
 4. The system claimedin claim 1, wherein at least one of said irrigation controllers isoperated locally via a user interface connected thereto.
 5. The systemclaimed in claim 1, wherein at least one of said irrigation controllersmonitors said at least one command on said communication bus.
 6. Thesystem claimed in claim 1, wherein at least one of said irrigationcontrollers, responsive to a receipt of said at least one command fromsaid at least one other irrigation controller, transmits anacknowledgement of said at least one received command to said at leastone other irrigation controller on said communication bus.
 7. The systemclaimed in claim 1, wherein a plurality of commands are transmitted onsaid communication bus from at least one of said controllers to said atleast one other controller, further comprising a bus management schemeto prevent collision of said plurality of commands on said communicationbus.
 8. The system claimed in claim 1, further comprising a centralcomputer, wherein said central computer is connected to said irrigationcontrollers on said communication bus; and said central computermonitors and/or controls at least one of said irrigation controllers. 9.The system claimed in claim 1, wherein said commands are selected from agroup comprising: adjust operation, review operation, sensor review,water schedule, and initiate watering.
 10. A method for a peer-to-peerdistributed network for management and/or control of irrigation,comprising the steps of: (A) providing a plurality of irrigationcontrollers connected via a communication bus, each of said irrigationcontrollers being responsive to commands received and capable ofinitiating and transmitting at least one command to at least one otherof said irrigation controllers; (B) transmitting at least one command,from at least one of said irrigation controllers, to said at least oneother irrigation controller via the communication bus; and (C)transmitting a response, responsive to said at least one transmittedcommand from said at least one irrigation controller and received bysaid at least one other irrigation controller, from said at least oneother irrigation controller to said at least one irrigation controller.11. The method claimed in claim 10, further comprising the step ofinitiating said at least one transmitted command from said at least oneirrigation controller to said at least one other irrigation controller.12. The method claimed in claim 10, further comprising the step ofoperating said plurality of irrigation controllers from a remotelocation via a wireless connection communicating therewith.
 13. Themethod claimed in claim 10, further comprising the step of operatingsaid plurality of irrigation controllers locally via a graphical userinterface connected thereto.
 14. The method claimed in claim 10, furthercomprising the step of monitoring, in at least one of said irrigationcontrollers, a plurality of commands including said at least one commandon said communication bus.
 15. The method claimed in claim 10, furthercomprising the step of transmitting an acknowledgement from one of saidirrigation controllers, responsive to a receipt of said at least onecommand from said at least one other controller, from said at least oneirrigation controller to said at least one other irrigation controlleron said communication bus.
 16. The method claimed in claim 10, furthercomprising the step of transmitting a plurality of commands includingsaid at least one command on said communication bus from at least one ofsaid irrigation controllers to at least one other of said irrigationcontrollers; further comprising the step of preventing collision of saidplurality of commands on said communication bus.
 17. The method claimedin claim 10, further comprising the step of providing a connection froma central computer to said plurality of irrigation controllers on saidcommunication bus, wherein said central computer monitors and/orcontrols at least one of said irrigation controllers.
 18. The methodclaimed in claim 10, wherein said commands are selected from a groupcomprising: adjust operation, review operation, sensor review, waterschedule, and initiate watering.
 19. A system for operating adistributed control network for irrigation management, comprising: (A) aplurality of irrigation controllers, each of said controllers beingresponsive to a command from an other controller; wherein saidcontrollers are capable of transmitting, receiving and responding to aplurality of commands, and wherein said controllers can be operated in alocal mode via a graphical user interface and in a remote mode via awireless connection; (B) a communication bus, connected to saidcontrollers, wherein said controllers are capable of monitoring saidcommands and said controllers are capable of acknowledging saidcommands; (C) a central computer, connected to said bus, communicatingwith said controllers via said bus; (D) a plurality of sensing devicesconnected to each of said controllers; and (E) a plurality of sprinklervalves connected to each of said controllers.
 20. A method for operatinga distributed control network for irrigation management, comprising thesteps of: (A) initiating a command at one of a plurality of irrigationcontrollers, wherein said controllers are connected to a plurality ofsensing devices, wherein said controllers are connected to a pluralityof sprinkler valves, and wherein said command can be a plurality ofcommands; (B) transmitting said command from said controller to an othercontroller via a communication bus; (C) monitoring said command on saidcommunication bus by said controller; (D) receiving said command at saidother controller; (E) acknowledging said command by said othercontroller; (F) acting on said command by said other controller; and (G)providing a connection from a central computer to said controllers onsaid communication bus.
 21. A method for providing a peer-to-peernetwork-enabled irrigation controller, comprising the steps of:providing an irrigation controller, wherein said irrigation controlleris configured to initiate and transmit at least one command to an otherirrigation controller; and said irrigation controller is configured toreceive a transmission including a command from said other irrigationcontroller, and to transmit an acknowledgement to said other irrigationcontroller responsive to the command from said other irrigationcontroller.
 22. A method as claimed in claim 21, further comprising thestep of connecting said irrigation controller to at least one sprinklervalve.
 23. A method as claimed in claim 21, further comprising the stepof connecting said irrigation controller to at least one sensing device.24. A method as claimed in claim 21, further comprising the step ofconnecting said irrigation controller to said other irrigationcontroller via a communication bus.
 25. A peer-to-peer network-enabledirrigation controller, comprising: (A) a plurality of satelliteirrigation controllers; and (B) a communications controller,communicating with each satellite irrigation controller of the pluralityof satellite irrigation controllers; wherein the communicationscontroller is a micro-controller in one of said satellite irrigationcontrollers, and is configured to initiate and transmit at least onecommand to an other of said irrigation controllers, and said irrigationcontroller is configured to receive and respond to a transmissionincluding a command from said other irrigation controller.
 26. Thedevice as claimed in claim 25, further comprising a port in saidcommunications controller for communication with a communication bus;wherein the communications controller, responsive to a transmission ofan event on the bus, initiates a transmission on the communication bus.27. The device as claimed in claim 26, wherein said event is a wateringschedule.
 28. The device as claimed in claim 26, further comprising atleast one sensor input connected to said satellite irrigationcontroller, wherein said event is based on an input from said at leastone sensor input.